Which refrigerant was commonly used before regulations phased it out due to ozone depletion?

The refrigerant that was commonly used before regulations phased it out due to its contribution to ozone depletion is R-12. This substance, also known as dichlorodifluoromethane, was widely utilized in refrigeration and air conditioning systems because of its effective thermal properties. However, because R-12 contains chlorine, its release into the atmosphere was found to cause significant damage to the ozone layer, leading to increased UV radiation reaching the Earth's surface.

As concerns about ozone depletion grew, international agreements such as the Montreal Protocol led to a phasedown of ozone-depleting substances, including R-12. This resulted in the transition to alternatives like R-134a and R-410A, which do not have the same adverse effects on the ozone layer. Understanding the history of refrigerants and their environmental impact is crucial for compliance with regulations and for making informed choices about modern refrigerants.